Carbon quantum dots have become widely researched due to their low toxicity and good biocompatibility. In addition, carbon quantum dots also possess other desired characteristics such as an adjustable light-emitting range and good photo stability. These carbon quantum dots have been prepared and studied for various applications, including optoelectronics and biomedicine, and have many other potential applications. However, certain methods of preparation are quite expensive and yield carbon quantum dots with undesirable properties. For instance, some of these carbon quantum dots may exhibit a short emission wavelength (e.g., <450 nm), a low photoelectric conversion efficiency, etc.
As a result, there is a need to provide an improved method of preparing carbon quantum dots. In particular, there is a need to provide a method of preparing carbon quantum dots that allows for the ability to control or tune the properties, such as the photophysical, electronic, and/or quantum confinement properties.